


For the Timeline's Sake

by Raging_Celiac



Series: Cassidy Snow AU [2]
Category: The Flash (TV 2014)
Genre: Angst and Hurt/Comfort, Canon-Typical Violence, F/M, Mild Gore, Sensory Deprivation, Symptoms of PTSD, Teenagers struggling with their mental health - Freeform, god it would've looked stupid if I'd left this in the character tags, wouldn't it?
Language: English
Status: In-Progress
Published: 2020-07-12
Updated: 2020-08-03
Packaged: 2021-03-05 00:41:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 10,374
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25165615
Author URL: https://archiveofourown.org/users/Raging_Celiac/pseuds/Raging_Celiac
Summary: DeVoe has been defeated, and world has been saved yet again. They did it.Caitlin had hoped that Team Flash would get a bit to take a breath, but the universe clearly has other plans: case in point, her and Barry's son from the future showing up at Joe's doorstep. Add on a new meta serial-killer, and building tensions from the meta-criminal underworld, and Team Flash has their work cut out for them if they want to save the city, Cassidy, and keep the changes to the timeline from spiraling out of control.
Relationships: Barry Allen/Caitlin Snow
Series: Cassidy Snow AU [2]
Series URL: https://archiveofourown.org/series/1807018
Comments: 9
Kudos: 23





	1. Cassidy

**There were** things that Caitlin expected. 

By this point, her list probably (definitely) included some _very_ disturbing items, but such was the life she had. Alternate personalities, superpowers, time travel - even saving the world - were all, in their own way and to their own extents, things she expected. This, though? This was _not_ on that list.

DeVoe was just about the oddest villain they had faced. To be fair, it was mainly the floating chair that Caitlin found odd, but everything about him was weird. In the end however, they’d beaten him, and for a moment, Caitlin had naively expected some breathing room. 

She stood in the doorway of the Lounge (how Joe had managed to nap there for years and not get noticed was a mystery to her), hands slack at her sides, breath caught in her windpipe. Words were difficult to produce at the moment: her mind had been seized by something that left it utterly speechless - and afraid. It wasn’t something she thought she could express verbally, despite the fact that she still had the urge to ask so many more questions - to talk to him, get inside his head. 

Their mop of blond hair could just be made out with the moonlight entering the Lounge. The beam was far enough to let him sleep, but also close enough to let her see the pale shade of honey that she was still struggling to wrap her head around. The sight didn’t settle with her - it didn’t fit in with everything else she’d seen, alternate universes and all. It wasn’t - it wasn’t right, because that mop of hair belonged to a teenager. 

_Her_ teenager. 

Who, just a few days prior, was at very real risk of becoming a vegetable. And while Caitlin cared about the seven billion other people in the world, of course, the thought that her teenager specifically was in that much danger and she had had not so much as a hint about their existence made part of her very, very angry. The particular breed that usually summoned Frost, but in this case, had not. Caitlin was left with it in its totality - it was hers.

It was a relief, really, that the party had been going as well as it had. Ralph had yet to say anything to mess things up, Ann-Marie was calm and clearly enjoying herself, and Caitlin felt relaxed for the first time in months. Whilst talking to Wally, Barry briefly flanked over to her, and his smile was wider than she had seen it for months. She wondered, for a moment, how she’d been able to resist that lovable of a face for so long. 

It was, officially, one year since Barry had returned from the Speedforce. Another month and it would be a year since the two of them actually started dating, which she had not planned for whatsoever - aside from the restaurant reservation, of course. 

The doorbell rang and, so as not to interrupt Barry’s conversation, she said, “I’ll get it.”

Barry’s smile had faltered just a bit at the interruption, but it recovered at her words. He turned back to Wally, and continued talking. 

She was met with the sight of a teen. Specifically, a teenage boy, a hair shorter than herself, with bandaids dotting his arms and legs, wearing shorts and a ratty t-shirt. The lines of his face were almost gaunt, and the green eyes that stared into hers were wary, yet Caitlin couldn’t say with confidence that they were entirely so. Blonde hair sat atop his head, and his sneakers were beat up, with small scuff marks and dried dirt covering them. What stood out most to Caitlin, though, was the light blue leather jacket tied around his waist - the exact same shade of blue that Frost loved wearing so much. 

“Can I help you?” she asked him. 

The boy stared dumbly at her for a space, before clearing his throat. “Uh,” his face flushed, “yeah, I was just…” he looked down at his shoes, and it took him several seconds, combined with a long sigh, to finally meet her eyes again, “... you’re Dr. Caitlin Snow, right?”

Caitlin frowned. “Yes.”

“And you, uhm,” he paused, clicking his teeth, glancing at the porch, before his eyes rocketed back to meet hers, “you know the Flash, right?”

Caitlin stilled for a moment, then put on a firm expression, “No.”

The teenager’s expression fell. For a few seconds, he seemed to be at a loss for words; panic rose in his eyes. The second before Caitlin was about to ask him to leave, he steeled himself, and she got a damn near perfect reflection of the face she wore when correcting something grossly incorrect. “In 2014 Eobard Thawne-”

“How do you know that name?” Caitlin narrowed her eyes. Klaxons of suspicion were blaring in her mind.

“Because,” the boy said, keeping his face far too close to Caitin’s ‘I have patience for now but I am running out’ for comfort, “I’m...” his expression faltered, and he swallowed, “... I’m your son, and I need your help.”

Caitlin’s mind came incredibly close to short-circuiting. For a moment, an intense numbness began to spread throughout her, but she stopped it. “What?”

“I’m your son,” the boy said quietly, “Cassidy Snow.”

“Snow?” Caitlin blinked. 

“Yes,” the boy nodded, a bit too hard, “Dad took your last name when you got married.”

“When I…” Caitlin blinked hard, “... you’re from the future?”

“Well,” the boy said, “you’d probably remember getting pregnant, right?”

Caitlin glanced down at her stomach, then back to the others, who had taken interest in the conversation. She shook her head. 

“T-that’s,” Caitlin blinked again. Suddenly, she noted that his face was horrifyingly similar to hers. “that’s impossible.”

The boy opened his mouth to speak, but closed it in short order. The conversation of the team had disappeared; she could feel their collective gaze on her back. Caitlin stared him down, heart hammering, as he closed his eyes.

Her jaw slackened as the teen’s hair turned white, and her eyes grew to dinner plates when the boy opened his eyes. Radiant blue-white irises stared into hers, and he asked, a bit more forcefully, “Really?”

Caitlin gawked at him for a space, completely dumbfounded, before she recovered her wits and silently stepped aside to let him into the house. She cast her eyes about the room, watching her friends’ faces all morph into various iterations of surprise. Cisco dropped his wine glass; Joe didn’t drop his glass, but his right hand twitched; Iris blinked several times, far too quickly; Ralph narrowed his eyes; Cecile shook her head; Wally craned his neck around Barry to get a look at the teenager, confusion swiftly giving way to bewilderment. Barry’s eyes darted between the boy and Caitlin, before they settled on Caitlin.

“Uh, Cait,” he said, “who is this?”

Caitlin didn’t want to look down at ‘Cassidy’. His face was too similar to hers. He was biting his lower lip. He’d just… just… no, that couldn’t - it couldn’t. She was the only one with her power set. At least… she thought she was. She supposed that it was entirely possible that DeVoe could make another meta like her; and if that were the case, entertaining this boy was a very poor idea. 

“What’s your name, buddy?” Barry asked, approaching the boy. Caitlin saw Cisco squint, his eyes jumping between her and ‘Cassidy’.

“C-cassidy,” the teenager answered, looking away, “C-cassdy Snow.”

Barry frowned. “Snow?”

“Mhm,” the boy gulped. 

Barry looked at Caitlin, raising an eyebrow. Caitlin stepped back, crossing her arms. “He isn’t. I’d know if I was pregnant, right?”

Barry nodded, looking back at the boy. “You said your last name was Snow?”

The teen inclined his head, humming another affirmative. The ends of his hair were becoming blonde again. 

“Okay,” Barry said slowly, briefly directing his gaze to Caitlin, then proceeding to divert back to the ‘Cassidy’, “tell us something only Caitlin would know about herself. Nothing dramatic, but something only she’d know. If you’re okay with that, Cait.”

Caitlin considered the teenager before her for a second, a scowl briefly crossing her face, before she slowly nodded.

Their hair was halfway blonde now. Cailtin crossed her arms more tightly, frowning deeply. ‘Cassidy’ eventually said, “I-in university, after your first year,” he glanced toward Caitlin, then back to Barry, “you were going to Ohio State, studying to go into optometry. Your mom sent you a letter telling you she approved of your area of study, and you switched majors and schools in order to get back at her.”

Caitlin promptly shook her head. “You could’ve just cold-read that. It’s not like my transfer wasn’t documented.”

The boy’s gaze flitted about the room, and he deflated. Barry was about to say something, but ‘Cassidy’ clenched his fists, and his hair, which had been getting more londe by the second, reversed course. 

“Okay,” he said, glaring at her, “fine. I know that you didn’t originally have your powers. After Zoom killed grandpa Henry, Dad traveled back in time and saved grandma Nora from the Reverse Flash,” Barry flinched slightly, and Caitlin’s frown collapsed. “Then, he reset the timeline, and as a result, you turned into Killer Frost in 2017.”

Everyone in the room stiffened. Caitlin’s frown had faltered, and she did a small doubletake. Barry, however, simply stared at ‘Cassidy’.

“‘Dad’?”

The teenager gulped. His hair began transitioning back to its original color at an impressive speed. “Uhm,” he said, “I, uh,” he swallowed thickly, before looking away. He was biting his lower lip ferociously. “... yeah.”

“You’re…” Barry’s voice was breathless, and he turned to Caitlin, “... are…?”

Caitlin had a distinct numb sensation in her chest, but she just managed to wag her head side to side, her eyes squarely on Cassidy. Barry tore his gaze away from hers and back toward Cassidy, and he weakly ran a hand through his hair. 

“I…” Barry said, “... I don’t know what to say, I’m gonna be honest here.”

Cassidy gave him a small nod, and looked at the ground. The members of Team Flash were all scrutinizing him, Caitlin, and Barry, to varying degrees. Cisco looked confused, and a bit amused, whereas Iris wore a face of concern, and Joe was slowly, in a cycle, looking at Cassidy, Caitlin, and Barry. 

“Hold on,” Ralph eventually said, a bit too loudly, “are we seriously talking about time travel right now?”

Cisco turned his eyes away from the trio near the door, shaking his head at Ralph, “Do you like, not pay attention to _anything_ we do here?”

“Hey,” Ralph snapped, “I know we get involved in some pretty weird stuff, but no one said bupkis about time travel!”

Ann-Marie started to cry. Cecile gave Ralph a harsh look before turning back to the baby. Ralph scowled, searching the room for support. 

Caitlin let out a long breath, “Okay,” she said, clearing her throat, “let’s get to STAR Labs. We’ll run some tests and then you can tell us how you go here, alright?”

She turned her eyes to Cassidy, who met them for long enough to give another “mhm”. He was still chewing his lower lip, hands taking refuge in his pockets. Caitlin’s mind flashed back to her first day at STAR Labs, staring at herself in the mirror, hands in the pocket of her coat, a dark one that she bought specifically for the commute to her new job - the same one she’d worn when she saw Barry run for the first time - with her route to work on the Central City metro stuffed into one of the pockets, an hour and a half before she actually had to leave, the image of professionalism… aside from the mauling she was giving her lower lip, and the nervousness in her eyes.

The memory was snuffed out as quick as it came, but the sheer uncertainty in Cassidy’s eyes was breaking through the numb sensation. It wasn’t something hysterical, or even particularly intense if she was completely honest. It wasn’t fear, nor was it entirely devoid of that emotion. It was mainly composed of concern, partnered with an acute sense of responsibility, complimented by an instinct that told her to grab Cassidy and just start driving to the Labs, hide him away from everything and anything that could worsen that terrible look on his face. 

Caitlin ignored it, holding her head high before curtly ordering Cassidy to come with her. He followed with an obedience that she hadn’t expected - she knew how Frost was in her case, and “following instructions” was completely antithetical to many of principles her alter ego prided herself on - and which made the corner of her that was looking rationally at the situation come to less than ideal conclusions. 

Part of her wanted to believe that this was all one of DeVoe’s plans. Cassidy was a mole; based on predictions about what had occurred over the four years since the Particle Accelerator exploded, cold-read against her history with Barry and possible security footage from STAR Labs, DeVoe had chosen a child that looked similar enough to a possible child she and Barry could produce, educated him, replicated her powers, and whose mission was to destroy Team Flash from inside, and accomplish his goals in the process. 

She stopped at a light, and glanced in the rearview mirror, catching a glimpse of Cassidy’s face. Her paranoia faltered. 

DeVoe would have, in any case, foreseen DNA testing as inevitable. She would find out within the next hour or so, either way. 

Despite her best attempts, she glanced back at Cassidy half a dozen more times on the route to the Labs. Half of the times were when she had to check behind her, which was not a smart decision for her or the teenager. Caitlin found herself pointedly not looking at him as she got him into the labs. She set to work taking a blood sample, hair sample, and everything necessary to determine the truth of this whole situation. 

Once Caitlin had everything working to look for genetic markers, she took a moment to clear her head (not so successful), before turning back to Cassidy, who was sitting on an observation table. Most of the team, aside from Joe and Cecile, crowded around the medbay door. 

Barry glanced at her briefly, before asking, “So, uh - Cassidy. How did you get here?”

Cassidy’s expression darkened for a moment. Something tense flashed in his eyes - something that Caitlin’s instincts assigned a distinctly _blue_ aspect, that she was finding odd mere moments after the idea popped into her head. The shadow was momentary, but from the faces of the team, it didn't go unnoticed. “I, uhm,” he licked his lips, “there’s this meta from… when I’m from. Calls himself Cicada.”

“Like the bug?” Cisco asked, shaking his head, “clearly, not my choice of names.”

“You almost had us calling DeVoe ‘The Teacher’,” Ralph said, making air quotes.

“He was a professor,” Cisco defended, “half these metas half some weird tragic life thing going on with their backstory. This dude taught college kids.”

“Anyways,” Iris said, offering a small, kind smile, “you were saying, Cassidy?”

“Uh, yeah, right,” Cassidy nodded, “Cicada, he - she - well, it's complicated - anyway, they targeted other metas. Metas like…” his eyes found the floor, “... me.”

“Cicada tried to hurt you?” Barry asked. He crossed his arms. 

Cassidy hummed an affirmative. He wasn’t looking at him.

“But you have Killer Frost’s powers,” Ralph frowned at him, “how did you get here? Those can’t let you time travel, right?” he gave Caitlin a somewhat hopeful look, “Right?”

Cassidy’s gaze lingered on Ralph a moment longer than it should have - his right arm, specifically. “I uh,” he chucked a bit, his cheeks pinking, “kinda had two. I got Killer frost from Mo - um, yeah. I got my speed from…” he trailed off, skittishly looking at Barry, “... you. They didn’t really mix that well. I was having problems with them before Cicada attacked - and, uh, during.”

Caitlin surveyed him, her machines diligently working in the background. She asked, “How bad was the problem?”

Cassidy’s attention jerked back to her. He hesitated before explaining, “My body's um - default state, I guess - was the homeostasis of a speedster. When I'd use my cold powers, I'd have to completely change homeostasis. When I'd go back to normal, I’d have these things that were kinda like hot flashes. They’d happen whenever I uh - reverted - and I’d sometimes have this massive buildup of lactic acid. It wouldn’t let me move for - well. It’s - it’s weird. I had a some other problems leading up to Cicada’s attack, too, and afterward, we decided that we should just get rid of my speed. So...” he paused minutely, "... y'know, nothing happened."

Cassidy flushed as silence settled in, and the team processed what they heard. Then, Cisco narrowed his eyes,

“Hold on,” he frowned, “we saw two speedsters exit the speed force this year. We couldn’t make out the other one - was that you?”

Cassidy flushed. “Yeah.”

“You said you were getting rid of your speed, though,” Cisco studied him with a bit of concern, “what did you do?”

There was a beat of silence before Cassidy answered, in a bitter tone, “I went too fast, I guess. We were using the thing Uncle Harry used to drain Da - uhm, you know, your speed,” he nodded to Barry, “I had my own suit and everything. I ended up just outside the city - near the windmills. I’ve been keeping my suit in my pocket.”

Cassidy reached inside one of his pockets, pulling out a red and yellow ring that had a lightning bolt engraved onto it. 

“No way,” Cisco shook his head, “who made that?”

“You did,” Cassidy said. Cisco squinted at it. 

“Really?”

Cassidy nodded, gripping the edges of the observation table. He peered just a tad past Caitlin, to where the devices running genetic testing were located. 

“Can I see it?” Cisco asked, squinting harder.

“Cisco,” Iris admonished, “don’t you think there are bigger issues to talk about right now?”

“Hey,” Cisco scowled, “I didn’t ask for this. How was I supposed to know Barry and Caitlin’s kid from the future was gonna show up? Least I can get is to geek out over-”

“Guys,” Barry sighed heavily, “we can talk about this later.”

“Why does fate always do this to me?” Cisco muttered. 

“We - we shouldn’t mess with the timeline,” Cassidy said, straightening himself, “I was taught that. Time shouldn’t be messed with unless you absolutely have to,” Caitlin was struck with another pang of resemblance, watching the way Cassidy held himself. It was the echo of the posture she always adopted when she was nervous, and she didn’t know what to do with that. The ring disappeared into Cassidy’s pocket, and he continued, with a bit more confidence, “I’ve been hiding so I didn’t mess with the whole DeVoe… thing. And, uh, those Earth X-ers.”

Barry nodded, looking concerned, but there was also a faint hint of approval, “How did you survive the year, then?”

Cassidy’s confidence disappeared. His shoulders tensed, and he set his jaw. “I… worked, I guess. There was this restaurant that let me work for them. They, uh, didn’t ask about my age - just let me work. I rented out part of someone else’s apartment for a place to stay and just… worked. I got rid of everything I had besides, uh,” he gestured to his clothes, “this stuff. I got rid of the papers and stuff, too, so there isn’t anything that could be linked back to me.”

“That’s… comprehensive," Barry said. 

Cassidy nodded, his face a deepening red. “I had to make sure - for the timeline.”

The emotion that had broken through the numbness spiked inside Caitlin. She asked, far sharper than she intended, “How old are you?”

Cassidy licked his lips, flicking his eyes up to the ceiling for a moment, before looking at the ground. He answered, quietly, “Seventeen.”

Caitlin’s eyes widened. Barry blinked several times. The rest of the team was worried too, probably, but Caitlin found the strange instinct in her chest growing at an enormous rate.

“Excuse me?” she asked, again, far sharper than she intended. She felt a surge of white hot anger, not so much at Cassidy, or at anyone in the room, but at the universe in general. The rational part of her was pointing out that the genetic test still hadn’t come back yet, and she might be sending the wrong message, but it didn’t do much to calm her down. 

Cassidy didn’t look back up this time. He nodded, but his attention was firmly retained by the floor. 

“I’m sorry you had to go through that,” Barry said gently, approaching Cassidy. 

Cassidy stiffened as Barry approached him. The speedster withdrew his hand, and drew back a bit. He put his hands in his pockets, and there was a small space of silence. The team watched Cassidy, and the teenager watched back, albeit far more skittishly. Eventually, the silence was shattered by the beeping that foretold the results of the genetic testing. Caitlin immediately turned toward the machine, throwing Barry a final glance before collecting the results with a sharp intake of breath. 

Her eyes swept over the genetic markers in less than two seconds, and another second later, she looked at Cassidy’s and had the wind knocked out of her. Caitlin straightened, her free hand absentmindedly smoothing over a flat section of her skirt. Slowly, she turned back to face the team, holding the results so they were facing her. 

She looked at Cassidy. Really looked at him, for the first time: she noticed some pimples clustered on the left side of his forehead - where she always got them as a teenager, no matter how hard she fought the tide - alongside the fact that his nose was nearly identical to hers, and how the lines of his face were a carbon-copy of her own. The only anomaly was his eyes… Barry’s eyes. 

Oh god. 

“They’re positive,” she said, just tearing her eyes away from Cassidy, “the markers - uhm, they - they’re a match for mine and Barry’s.”

At her words, the team’s attention jumped in full over to Cassidy. Barry’s eyes were the first to make the leap, and they swiftly searched the whole of the teenager in front of him. Cassidy went beet red, and looked at the ground. 

Just then, however, the Meta Alert sounded. Cisco rushed over to the Cortex’s main console. 

“It’s on…” Cisco squinted at the screen, “... oh no.”

Barry, cocked his head to the side, “What’s ‘oh no’?”

Cisco looked up at him, a tad nervous. “He’s just down the street.”

On the large monitors on the back wall, traffic cam images of a man wearing a black facemask and leather jacket appeared. He was throwing a cop over his shoulder and straight onto the concrete. Another cop came from behind him, and clubbed him over the head with it. The meta fell to the ground, and blue electricity began to crackle over his body. The officer with the baton went to cuff him, but the meta swept his legs out from under him, and proceeded to cold clock his partner, who had risen to his feet, straight a wall hard enough to crack it. 

“I don’t have a suit,” Barry said, shaking his head.

Cisco frowned. “I think-”

“Your back closet!” Cassidy cut in, glancing at the traffic cam. The meta stomped onto one of the officer’s faces, “You have your 2014 suit in the back closet, right? That's where they are in the - y'know."

Cassidy got a few odd looks (Cisco’s appeared more perturbed than anybody else's), but Barry sped away nonetheless, and within moments, he was out on the street, hands resting on his hips. Ralph rushed out of the lab as well, expanding his suit as he did. 

Cassidy did a poor job of hiding his interest in the fight, glancing away for one second, directly back the next, slightly above the screen after that, and then at the other screen. Caitlin supposed that she should have been paying more attention to her position at the main console, but… 

Barry evacuated both cops before turning his attention to the meta, punching him in the solar plexus. Cassidy’s eyes widened at that sight. The meta doubled over, knees buckling, falling onto his back. Barry went to cuff him casually, as the blue lightning arched around the meta. Barry leaned down to cuff him, and by the motion of his free hand, Caitlin could tell he made a wisecrack. In the middle of said wisecrack, however, the meta kicked him in the chest with both legs. Barry flew at least two dozen feet before he hit solid earth; Cisco switched traffic cams just in time to watch the speedster crush the windshield of a rather unfortunate chevy. 

Ralph, a bit breathlessly, supplied over the comms, _“Don’t worry guys, I see him! Now it's - JESUS CHRIST!”_

Cisco switched one of the screens so they had a look at Ralph, to witness him barely dodge an SUV. It was barreling down the street, straight toward the meta. Barry was still pulling himself to his feet - and one look at the telemetry of the suit told Caitlin something very ill-timed. 

“Barry,” she said, “your pelvis is cracked.”

 _“It’s fine, Caitlin,”_ was Barry’s response as he got everyone out of the car and parked it, mere feet from the meta. Caitlin snorted to herself, drawing a turn of Cassidy's head. He looked away before she could properly meet his eyes.

 _“I’m right behind you, Barry!”_ Ralph said. 

The pair of heroes took up positions in front and behind the meta, who was tapping the ground with his foot. 

_“Ralph, take out your cuffs,”_ Barry said, not a moment before applying several more speed-punches to him, knocking the man flat on his back once again. Barry put his hands back onto his hips, wincing as Ralph rushed over to put cuffs on the criminal. Ralph was leaning down to cuff him when the meta pulled the same move as last time, and kicked him in the chest. He went flying, but this time he soared far above the highest building near him. Ralph screamed. Barry cursed and sped off to catch him.

Cassidy stared at the footage of the meta running away, straight into traffic, tensing as Ralph’s distress filled the cortex. Cars struggled to make way, in what was probably a cacophony of horns and squeaking brakes. Cassidy’s fists clenched when the meta began the traffic jam, and he started to glare as a car stopped in front of him. 

Caitlin watched Ralph’s trajectory: he was several hundred feet up in the air, in an arc that would take at least another thirty seconds to finish. She exchanged a glance with Cisco, before her gaze was drawn back toward Cassidy, who was visibly shaking as the meta grabbed a man from the passenger side of the car, with his seat belt on, and pressed a knife to his neck.

“It’ll be okay,” Iris said, placing a hand on Cassidy’s shoulder. “Barry will get him, don’t-”

Iris abruptly fell silent. Her eyes widened. A second afterward, Cassidy’s vibrating grew fast enough that it disrupted the line of his frame. Caitlin rose to her feet along with Cisco. 

She opened her mouth to speak, but Cassidy wheeled around. The boy’s eyes were glowing red. Just as she was processing that, he sped out of the Cortex, a trail of white and yellow lightning in his wake.


	2. In The Negative

**Summary for the Chapter:**

> Content warning for some gore and a stabbing, along with the effects thereafter. Yes, this is chapter two. Yes, I love these characters. I swear!

**Cassidy was** out of the building before any of them had the chance to stop him. 

“Hey, uh,” Cisco said, “didn’t he say that he _lost_ his speed? Or was I just hearing things?”

Caitlin was staring at the spot where Cassidy had been standing mere seconds earlier, her mind producing images that she very much didn’t want it to. From the brief glances Caitlin gave Cisco and Iris, she got the impression they were in the same state she was. Well, maybe not the exact same, considering that it wasn’t _their_ child from the future that had just used a superpower they claimed to not have, and who looked just like-

Caitlin shook her head furiously, and sat back down at the same time as Cisco, just when Barry said over the comms, _“Cisco, did you just say something about speed?”_

Cisco’s gaze flicked over to Caitlin, before he responded, “Well, uh, Cassidy just sped out of the Cortex looking like Reverse Flash, so, I’d say so.”

_"Excuse me?”_

“Yeah, man! Red eyes and all,” Cisco said, typing commands into the main console, “I’m trying to-”

Cisco scowled, then rolled his eyes. 

“Right, nevermind! We don’t have a satellite, remember?” he chuckled, with absolutely no humor. 

Moments after the words left his mouth, yellow and white lightning blazed past one of the traffic cams. 

“Guys,” Iris began, “he’s-”

“Going after for the meta.” Caitlin finished, voice tight. 

_“What? What do you mean ‘he’s going after the meta’?”_

Seconds after the words left Barry’s mouth, white and yellow lightning appeared on one of the traffic cams again; specifically, the cam depicting the meta holding a knife to the man’s throat. In a blur of lightning, the civilian fell onto his knees, gasping, while the white and yellow lightning disappeared from frame. 

_“Guys!”_

“Cassidy’s heading back to the labs,” Cisco said, switching his screens to a view of the Pipeline’s entrance, “I’m gonna stop him.”

“Cisco!” Iris said, “Are you seriously going to attack your own nephew?”

“I’m not! And he’s the one who tried to fight a meta! You heard what he said, too - the last time he had speed, he had serious health problems!” Cisco shot back, opening up a breach. Eyes moving back and forth between the traffic cams and her friends, Caitlin found that her voice had elected to abstain from contributing to the conversation. Instead, she stood up, and made to follow Cisco through the breach. 

“Cait,” Cisco said, “you don’t-”

Caitlin leveled him with a glare that made him pause for a moment; in that moment, Cassidy passed the second to last traffic cam leading up to STAR labs. Cisco jumped into the breach, and Caitlin did the same a moment later; Iris tried to get into it, but it closed on her. Caitlin thought she heard the woman huff as she and Cisco appeared in the Pipeline. 

Cisco looked to Caitlin, who was just about to give him a nod of approval when the both of them were thrown against the walls of the Pipeline. Caitlin barely had the time to process the yellow and white lightning rocketing towards them before her world was thrown ajar, and the back of her head lit up with pain. She grunted, pulling herself to her feet and helping Cisco to his before both of them began sprinting down the Pipeline (no, she did not remember that she wasn’t wearing the shoes for this), checking each room frantically. 

It was in the seventh cell that they found Cassidy. Key word: Cassidy. 

_Just_ Cassidy. 

The teen was in front of the cell door, whose outer door had been shut, lying face down, with tendrils of his lightning sputtering out around him - some of which, to Caitlin’s confoundment, seemed pinkish. That detail was hardly the most dominant thing in her mind, however: far larger was the mixture of expletives and concern, which trampled over such inconsequential oddities, and redirected the entirety of her focus to solving this situation, right fucking now. 

She had knelt next to him and turned him over in short order, and saw yet more pinkish coloring, clustered around his eyes. He was still breathing, but to her bafflement, that same pinkish hue began to fade just as soon as she noticed it. Caitlin brushed past her confusion, however, and attempted to take Cassidy’s pulse from his neck. She silently counted to fifteen, each second reminiscent of an eternity rather than any measurable unit of time; she almost lost count twice, whilst parts of her, amidst the chaos, shouted at each other over how she had just met this kid less than five hours ago, and that the genetic test could’ve been wrong - while the other vehemently rebuffed that she hadn’t botched a test in years, and even if this _was_ all a hoax, this was still a child she was dealing with. And for some reason _he didn’t have a pulse-_

Caitlin finished her count to fifteen just as she registered the gust of air signifying Barry’s arrival. She didn’t move her gaze from Cassidy as she moved to check his pulse on his wrist. She counted to fifteen again, as Barry and Cisco exchanged some words. Caitlin was sure she heard them, and equally confident that where the meta was was a secondary concern for her right then. 

Cassidy said he lost his speed - if that was the case, how was he using these powers? Why were his eyes red? She supposed this state - still breathing, with no measurable pulse - was akin to Barry’s coma, but Cassidy hadn’t been struck by lightning. Or… he hadn’t mentioned that. Had an event like that jump started his powers again? If so, why wasn’t he _already_ in a coma? Why wasn’t he waking up?

Caitlin jerked away when Barry put a hand on her shoulder. She had grabbed Cassidy’s other wrist (his skin was getting really, really warm) when Barry put his hand on her shoulder again, firmer this time, and she tore her eyes off Cassidy to look at him. 

Her heart skipped a beat when she saw Barry’s eyes, for a reason she wasn’t able to pinpoint. 

“It,” she began, a sect of her feeling that this was very superfluous, “he’s breathing. He - he doesn’t have a pulse. He didn’t mention anything that could have restarted his powers, so I don’t…” she trailed off, her hold on Cassidy’s limp wrist tightening, “... we need to get him to the medbay. We - you need to set him up with an IV and a heart rate monitor, and grab some of your calorie bars just in case he burns through that too. I’ll be right behind you.”

Barry gazed at Cassidy, and she had the sneaking suspicion he had drawn the moment out, but he nodded and she allowed him to gently pick up Cassidy bridal style. He sped away as she began to stand up, her eyes finding Cisco, who wore a face that held the hint of offense. 

“He used my code,” Cisco said dully, as Caitlin drew herself to his eye level, “my emergency code.”

“We can focus on that later,” Caitlin said, brushing past him. 

“It was Dante’s birthday,” Cisco murmured, which Caitlin heard just before she disappeared around the corner. Caitlin paused, minutely, struck with a pang of guilt that barely made a dent in her current emotional state, which only made her feel worse. She took in a breath and blew it out, trying her best to sweep the slate clean, and get herself to focus on what she needed to do, kid from the future factored in or not. 

Caitlin got to work measuring Cassidy’s vitals as soon as she was close enough, the rest of Team Flash giving her space, although Ralph and Barry winced on occasion. 

By the time Caitlin was done, Cassidy’s breathing had improved, and when she hooked up the heart rate monitor, she was relieved to see that it was two hundred bpm (which was far from safe for any normal person, but she didn’t see any signs of a heart attack). However, Cassidy’s lactic acid levels were far above normal, and he was running a fever. 

The team was quiet as she worked. Barry lingered on Cassidy’s right, just out of her way, but by far the closest member of the team aside from herself. She could have been able to tell he was stressed from his body language alone, but the look in his eyes was something that only added to her stress; concern, with a hint of trepidation, and the slight widening of his eyes seemed to bore into her, even though she knew what she was seeing had nothing to do with her. Not really. 

Cassidy stirred once or twice, where he shivered harshly, winced at the lights of the medbay, then closed his eyes - although, not before he stared at Caitlin with bleary familiarity. Caitlin did her best to shelve that for the moment. 

Once she was certain Cassidy was stable, she wordlessly gestured Barry over to a free stool, “He’s asleep,” she said, “come on, you cracked your pelvis. Let me take a look at it.”

Barry hesitated, before he sat down at the stool. Caitlin said, whilst pulling out bandages, “I’ll get to you next, Ralph. Find some place to sit down.”

Ralph followed her instructions. Patching up Barry was something she did with a practiced blank expression, from cleaning up bruises to bandaging his back. Barry didn’t say anything as she did her thing: instead, he poorly hid his focus, which was squarely on Cassidy, whose heart rate had finally fallen to a normal level. The monitor’s steady rhythm of notes was the only sound filling the silence, aside from Cassidy’s breathing, which was so quiet that it was barely discernible. 

Caitlin finished treating Barry, who immediately grabbed another stool and sat down next to Cassidy, after giving her a thank you, encouraging smile, and peck on the cheek. If Caitlin was honest, none of that helped her feel much better. 

She had the nagging feeling that she wasn’t exactly sympathetic toward Ralph when treating the wound to his chest, and by some small miracle none of his ribs were broken, and his sternum was fine. Caitlin cleaned the wound anyways and gave Ralph ibuprofen, before collecting the results of Cassidy’s blood tests. 

She scrutinized the results closely, and sighed in frustration. There _were_ tachyons in his system in both tests, but the test she had originally run showed his cells not regenerating like Barry’s - they were dormant. However, the second test showed that they were… and that many were in the process of ceasing to do so, as well. At the same time, however, none of his cells showed signs of degeneration - Cassidy wasn’t dying. He had a connection to the speedforce, but he couldn’t use his powers?

Caitlin put a hand to her forehead, glancing at Cassidy, before re-reading the results. 

None of it made sense. How could he have suddenly regained his speed? She had two blood tests in front of her, and it was obvious that Cassidy had effectively lost his speed, yet less than an hour ago he had somehow regained it, with no signs of how. V9 was off the table, because it would have been active when she ran the first blood test, and she hadn’t found anything on Cassidy’s person to supply him with tachyons, and no foreign objects inside him, either. 

“Cait?” Barry’s voice made her jump a bit, “Are you okay?”

Caitlin’s eyes shot up to meet his (she didn’t look at her son from the future first, he was stable and asleep, there would be absolutely no reason to), “This doesn’t make sense,” she sighed heavily, “he has tachyons in his system - he should be able to access his speed, but his cells aren’t regenerating,” Caitlin walked up to Barry and shoved the blood tests in front of him, “two hours ago, anyway. The most recent blood test shows that his cells were beginning to regenerate, though, look,” she jabbed a finger at the results, “but they simultaneously show signs of reverting back to their dormant state, and - see?” 

Barry frowned at the results, “He doesn’t have V9 in his system.”

Caitlin bit her lip, “Yep.”

She watched Barry study the results intently for several moments, before shaking his head, “Alright, yeah, this is just plain weird.” 

Caitlin gave the results to him and stepped back, reaching up to brush some hair behind her ear, only to be met with air. 

* * *

_Cassidy didn’t understand it._

_Any of it._

_At all._

_Had AP calculus always been this annoying? Mom said she hadn’t been a fan, but Uncle Cisco definitely disagreed. Granted, Uncle Cisco was like, a modern Einstein, so Cassidy supposed that answer could be taken with a grain of salt. Aunt Iris said his father had taken it and didn’t enjoy the experience, but… yeah, now was not the time to think about his father._

_Or ever._

_Internally, Cassidy realized that that wasn’t the best thought to have about his father, but he shook both the feeling and the thought off, failing to succeed one both fronts. He stuffed his homework into his bag, hit only a twinge of dismay at how disorganized it was: his folders were all thick, filled with packets and sheets that he had forced himself to review first, leaving him drained for brain power when AP calculus reared its head._

_Cassidy shook his head again. His homework was done: his Sunday was now officially his. All four hours he had left. Mmm._

_The sun was already setting. Mom was working on a meta-case with the rest of the Team, and from the way Molly had whined outside his door today, no-one had taken her for a walk today. Cassidy rubbed his eyes, sighing, before exiting his room._

_Barely two seconds after he got out, he heard paws skittering across the wood paneling of his house. Cassidy huffed, smiling a bit, descending the stairs just as Molly skidded to a halt in front of him, smiling, with her tail wagging enthusiastically._

_Molly was their dog: seventy pounds of german shepherd, who was approaching the end of her life, but Cassidy didn’t want to think about that either. Even at ten, anyhow, and with her joint and hip problems, she still needed at least a mile-long walk every day. Normally, Mom fit it into her schedule, but obviously, she was doing hero stuff._

_“You shouldn’t run like that,” Cassidy said, scratching behind her ears. “It’s bad for your hips, Molls. Come on.”_

_Molly’s brown eyes saddened a bit, but she licked his outstretched arm anyways. Enthusiastically. Cassidy smiled a bit, and gave her another scratch. Then he stood, and turned toward the hanger for Molly’s leash. He heard her panting behind him, and she obediently sat down, leaning against his leg. Cassidy hooked the leash to Molly’s collar, and began to reach for the plastic bags that would (inevitably) hold her poop. Molly panted, and a paw struck out toward the leash, which Cassidy snatched out of reach a second after contact._

_“Excited?” he asked, wadding up a few bags and shoving them into his pockets. Molly wagged her tail and reached another paw out toward her leash. Cassidy laughed, taking one final bag to be safe, before attaching the leash to Molly’s collar._

_“Less pulling today, okay? The vet said that you need to rest,” Cassidy said, pushing open the door._

_Molly, of course, sped out onto the front porch. She didn’t go any farther, though, on account of the many hours of training Mom had put her through. Molly looked out on the neighborhood that she’d seen thousands of times over her life, smiling wide. Cassidy shook his head, his lips curling up just a bit._

_The trees overhead were halfway between Autumn and Winter; enough leaves had coated the ground to provide the occasional_ crunch _, but plenty still clung to their branches. The sunset filtered and fractured through the tree branches, making strips of yellow-orange light across the sidewalks and road. They didn’t encounter any other dogs, but Molly still watched the houses she knew held some. She pulled some, but after the first five minutes she’d stopped._

_Cassidy scanned the area around him lazily all throughout the walk. Mom had been very clear with him for years now - enough people knew who his father was, or who Mom was, that it could be incredibly dangerous to be outside at night, especially alone. However, seeing as how nothing had ever happened to him, the only note he made about the figure who appeared once he entered the local park was that they had a weirdly long coat._

_He didn’t catch onto the danger until Molly suddenly froze. Cassidy frowned, glancing around himself as she sniffed the air, before turning around and growling behind them. Cassidy corrected the twist in her leash before he turned around._

_He saw that some person, holding something he couldn’t make out in their right hand. They were a few heads taller than him, and while their coat made their outline big, Uncle Diggle's training made him suspect that they weren’t that large in reality._

_“Uh,” Cassidy chuckled, as Molly growled again. He tugged a bit on her leash, “I’m sorry about her. She’s really sweet, I swear.”_

_The person didn’t respond. Instead they threw the object in their hand, which made Cassidy jump back. It landed right where he’d been standing, and up close he saw that it looked like a misshapen lightning bolt. Ridges along its faces began to glow orange, and white and yellow lightning erupted off of his skin and funneled toward the piece of metal. Cassidy spluttered something, before closing his eyes._

_He knew where to find his cold powers by now: they were where his humanity and anger intersected, right up against his tendency to push others away yet not all far from the part of him that wanted to help people. He felt the cold wash over him, opening his eyes to see the piece of metal go flying back into his attacker’s hand. Molly barked, and Cassidy let go of her leash, raising his hands just as she started to run at Cicada._

_Then Cicada threw his dagger, which sliced through the air and right through Molly’s neck, just as Cassidy began to fire ice at them. He stopped when Molly let out a whine, her body arcing in the air, red splatter coming out of her neck. He watched as her head was separated from her body, slack jawed, feeling a wave of complete and utter numbness crash onto him._

_Then Molly’s body hit the ground. Her body fell first, then her head, which rolled toward him, contorted in alarm and pain. Cassidy gawked at it, then at Cicada, who recalled their dagger. Water threatened Cassidy’s eyes, before he let out a cry and blast Cicada with everything he had._

_Cicada went flying, but Cassidy wasn’t done with him. He sprinted right past Molly’s body to hit Cicada with another torrent of ice, but they threw their dagger at him right before he could. Cassidy threw himself to the side, scrambling to his feet as the dagger flew back into Cicada’s hands._

_Cassidy threw more ice, but was interrupted again by Cicada throwing his dagger. Cassidy ducked under it this time, and just missed Cicada, who had started to run toward him. Cassidy sprayed at the meta even more, but Cicada was faster than he thought. He was discerning the outline of their mask when he felt something slam into his back._

_Cassidy lost his footing, and the flow of ice stopped. As he tried to right himself, he felt fire light up his right shoulder. Cassidy stumbled again, this time losing his footing entirely. When he hit the ground, he felt another lance of fire in his shoulder. Cassidy winced, trying to push himself to his feet, feeling something warm and damp on his back. He sucked in a breath as he pushed himself up, which made his shoulder light up again, along with his legs. He fell back to the ground, watching Cicada walk up to him, wanting to move while he felt his own energy draining away. As his breathing grew shallow, he finally realized what had just happened._

_"I-” Cassidy sputtered, “w-what do you want with me?”_

_Cicada was crouched in front of him now. Their eyes were brown. They glanced at his shoulder, before pulling back their hood to reveal a woman with blonde hair. She pulled the mask loose, placing her other hand around their dagger._

_“I’m saving you from something worse,” the woman said, looking him directly in the eyes. Cassidy cried out in pain she yanked her dagger out of his body, using her other hand to keep him steady. She pulled her hood over her head and put her mask back on just as Cassidy heard the telltale sound of a speedster arriving on the scene (was it always that quiet?)._

_“Get away from him!” Uncle Wally screamed, but as he got closer, he lost his speed. By the time he had thrown himself into Cicada, he was only going slightly faster than a bike._

_Nonetheless, Cicada and Uncle Wally toppled to the ground. Cassidy tired to sit up, but everything felt incredibly heavy. That, combined with the searing pain that radiated off of where he’d been hit, made him fall back against the Earth. He stared up at the sky, awash with dark purples and faint, oranges. Each breath felt like lifting one of Uncle Renee's old dumbbells._

_Eventually, Uncle Cisco appeared next to him. Cassidy glanced toward Uncle Wally, who was still fighting Cicada, aware that Uncle Cisco was speaking to him and simultaneously unable to hear him. His head lolled forward, and his eyes shut for a moment, before Uncle Cisco forced them up, and ushered him into the breach._

_Cassidy saw Mom standing at the operating table, in gloves and face mask. Aunt Lisa was holding the first aid kit, and the last thing Cassidy saw before he lost consciousness were the faces of his family, twisted up with concern._

* * *

Caitlin nearly lost track of the time it took Wally to get back to them. She assumed a vigil to Cassidy’s right, keeping track of his vitals, watching his cells settle back into a normal-ish state, not all too dissimilar to hers, which was, to Dr. Caitlin Snow MD, terribly fascinating. To the rest of Caitlin, it was disquieting; she hadn’t seen anything like this before, and she had no idea of how to treat what was happening to Cassidy. Or, even if this had a treatment in the first place. She saw Barry’s shadow pass over her instruments after a space, to which she nodded, before re-focusing on Cassidy’s vitals. 

“His heartbeat is down a normal level,” Barry observed, “but the amount of tachyons in his system is still tiny. Huh.”

Caitlin hummed, throwing a glance toward Cassidy’s sleeping form, “he has tachyons,” she said, “so he still has some connection to the speed force. I’m thinking he might’ve been dealing with the same problem you had with Blackout.”

Barry briefly looked at Cassidy, before nodding, “I guess. I mean, arriving in the past wouldn’t exactly have been easy for him. Let alone living on his own for a year.”

Caitlin honestly wasn’t sure how she would’ve responded. She was in agreement, but a portion of her very much didn’t want to think about a teenager - _her_ teenager - alone in the world at sixteen, having to weigh every action he took against the possible effects it might have on time itself. That was a tad dark, and Caitlin couldn’t say for certain how she was going to deal with someone who had to live in that mindset for so long. 

“I, uh,” Barry said, “checked the newspaper from 2024. No - no changes.”

Caitlin stopped her study of Cassidy’s vitals, and slowly turned to look at him. Her eyes darted over to Cassidy, before she grabbed his hand, squeezing it. Barry squeezed back, but he wasn’t looking at her: rather, his attention settled on his son, just as he swallowed. 

“Yeah,” Barry nodded, “thanks.”

Caitlin gave Cassidy’s vitals a final scan before standing up. She grabbed Barry’s other hand, opening her mouth to say something comforting, but she was cut off as Wally sped into the room. Cisco and Iris yelped at their positions in the cortex; they’d spent the past hour searching for anything they could that showed Cassidy, so they could get rid of it before something happened. Neither of them had made any exclamations, which was probably good, but easily have been bad, and Caitlin knew that whether they did or not mattered very little to the feeling that had broken through her numbness. 

Not the best view to take, but Caitlin already felt an attachment to Cassidy, which was stronger than she expected it to be, yet that also didn’t override her other thoughts. It had swiftly become background noise, motivating her to refresh her images, run over her test results just one more time, to be absolutely _sure_ nothing was wrong. 

“Okay,” Wally panted, “I have some bad news.”

“Now don’t get my hopes up too high," Cisco muttered. 

“I have some good news as well,” Wally said, turning to Barry and Caitlin, before his eyes caught onto Cassidy, “Cassidy - uh, what happened?”

The four members of Team Flash glanced amongst each other for a moment. Then, clearing his throat, Barry offered, “A meta attacked just after you left. Ralph and I went to fight it and… Cassidy took it upon himself to fight him as well. He’s been out ever since we beat the meta.”

Wally blinked, then shook his head, “Alright then. Well, I found the Legends, and had Gideon run a test on Cassidy’s blood,” he took out the small vial of blood Caitlin had collected for him, “and she gave me the bad news.”

Barry’s eyes flickered over to the medbay, “What bad news?”

“We can’t take him back on the _Waverider,_ ” Wally said, “Gideon said he has too many negative tachyons. He’ll vaporize the ship if he takes a single step onboard.”

“‘Negative Tachyons’?” Cisco asked, shaking his head, “what, the Speedforce has a dark side now?”

Wally smiled a bit, but he stifled it in short order, “I actually… don’t know. Gideon wouldn’t tell me much about it.”

“What?” Caitlin asked, “Why not?”

“She said,” Wally sighed, “she said that it would affect the timeline if you guys knew anything substantial about them. That since Cassidy had been in the past so long, these events were supposed to play out now, and you guys had to learn about Negative Tachyons on your own for it to go down correctly.”

Team Flash fell silent. Eventually, Iris asked, “So this is… this is the future now? The Timeline has already changed?”

Wally nodded, “Yeah. She wasn’t big on details, either, so I don’t know what’s gonna happen. Just that…” he licked his lips, “... well, it doesn’t matter if he - if he gets home or not.”

Caitlin blinked, then shook her head profusely, “What does that mean?”

Wally fell silent. "I... okay," he took a breath, “the Legends have a theory that some events are ‘soft’. If you change them, not much else will change. Other events are hard - you can’t change them without majorly affecting the timeline. The way Gideon said it, I think Cassidy being here changed soft events - stuff that doesn’t matter in the grand scheme of things.”

Caitlin narrowed her eyes. "You said-"

"Yeah," Wally cut her off, "I know."

The the conversation collapsed, until Barry said, “So we can help him get home without changing things,” 

“Probably, yeah,” Wally nodded, hands in his pockets, “and Gideon did tell me one thing about the future: Cassidy needs his speed back before he can go home.”

“Well that’s not a problem,” Cisco said, “he clearly still has it. We’ll just give him some tachyons and bam - problem solved.”

“Sure,” Wally said, “whatever works. All we hav-”

“Mom?” a voice from the medbay cut him off, making everyone look over. Caitlin stiffened. She locked eyes with Barry, and scanned the uncertain faces of the team before entering. Caitlin hoped that her trepidation wasn’t visible. 

She approached Cassidy slowly, as he moved to sit up, removing the IV from his arm. Caitlin reached out to stop him, but that only made him flinch back, jerking the IV so hard that it fell over. Caitlin managed to catch it before it hit the ground, all too aware of Cassidy’s startled look. 

“Don’t worry,” Caitlin said hastily, “it’s alright. You’re in the medbay. You’re safe.”

Cassidy took a moment before he said, “Yeah.”

Caitlin inclined her head, and felt word drying up in her mouth. She looked at the team, then said, whilst smiling tightly, “We were just talking to Wally. He went to the _Waverider,_ and your presence here doesn’t seem to be changing much at all.”

Cassidy swallowed, and said, “Yeah. That’s good.”

The rest of the team filed into the medbay, spearheaded by Barry, who asked, “Hey, you feeling alright?”

Cassidy nodded slowly, glancing at the IV. Caitlin followed his eyes, and said, “it’s just some nutrients. Your body burned at least 2000 calories when you ran after that meta.”

Cassidy stilled, and his eyes grew to dinner plates, “What?”

Caitlin’s smile collapsed. “You don’t remember?”

“I…” Cassidy looked down at his hands, “... I remember getting - the meta was about to hurt that guy and I - no, I remember now. Yeah. I remember.”

“That’s good,” Caitlin said, “it means you don’t have a concussion.”

Cassidy’s eyes were still on his hands as he let out a long breath, “Yep. That’s good.”

Barry cleared his throat, “Well, Cassidy,” his child’s ( _yours too, y’know)_ eyes jumped over to him, “Wally visited the Legends while you were out. You want to tell him what you got, Wally?”

Wally told Cassidy everything he’d told the team. By the end, Cassidy as a bit paler than he had been, and he had laid back down on the bed, staring at the ceiling. 

Eventually, he said, “No.”

Wally shook his head, “I now this isn’t ideal, but-”

“No!” Cassidy shot up to a sitting position, glaring at Wally, “I can’t stay here!”

“Cassidy,” Barry said, “please, calm down. You know why-”

“I don’t care what Gideon said!” Cassidy’s eyes started to glow, “Me _being_ here has killed people! I can’t-”

“Hey,” Barry said, holding up a hand, “you don't know that. And even if you being here did - it doesn't matter. You can't control time, okay?"

Cassidy’s hair began to turn white at the roots, “I can control how long I stay here. I don’t care what Gideon said - I need to get home, _now!”_

“Hey!” Caitlin snapped, “You don’t get to talk to him like that!”

That stopped Cassidy in his tracks. He froze, his gaze snapping onto Caitlin, and all of the anger drained out of him. His hair turned brown, and his eyes stopped glowing. Caitlin saw fear in them, which took her a moment to process. 

“... I’m sorry,” he eventually said, staring at his lap, “I - I just need to get home. Really badly.”

Barry offered him a smile, and stepped toward Cassidy, “It’s okay. And we’ll get you home, alright? I promise.”

Cassidy didn’t return his gaze for several moments. When he did, all he provided a quiet “Mmm-hmm”, before giving Wally an “I’m sorry” and falling silent. 

* * *

Caitlin leaned against the doorway of the lounge, frowning. Most of her shock had subsided by now, but it felt… necessary, to do this. She and Barry had to get home soon, but both of them had been procrastinating on that particular item for the past few hours; Barry had started working through his backlog of cases, while Caitlin did yet more tests on Cassidy, including a brainscan of him while he was using his cold powers, which, like the blood test, had only created more questions than answers. 

Cassidy claimed to remember what he did when he used his powers. That should have been by all rights impossible, but his brain activity, unlike hers, only differed on which centers of his brain were being used. Unlike hers, his brain wasn’t storing memories in such a way that they were only accessible when he used his cold powers, which baffled and worried Caitlin. 

She shook her head. Now wasn’t the time to think about this. Ralph had agreed to stay overnight at the labs with Cassidy (he protested that, but gave in after she tried out a stern look), and she and Barry really needed to get home. Nonetheless, Caitlin remained where she was, her focus in a vice grip emanating from Cassidy’s sleeping form. It held her in place, subtle and insurmountable, demanding that she keep an eye on him - after all, Ralph wasn’t the fighter the Barry was, nor was he as clever as Cisco. He had a good eye for small details, but Iris definitely matched that quality at the least, and had spent her life with a cop dad - she knew how to defend herself. 

Caitlin bit her lower lip, shaking her head. She wrenched herself out of the vice grip just as Barry came around the corner. 

His hands were in his pockets, and his shoulders were slumped. He said quietly, “I checked the paper again. Nothing’s changed.”

Caitlin stepped toward him and took his hands again, “We have time to change that.”

Barry looked over her and into the Lounge, “I hope so.”

“We will,” Caitlin said, firmer this time, “hey, we will. Don’t think like that - we have five more years to change that, alright? We have bigger problems right now.”

Barry sighed heavily, letting go of her hands and pulling her close, “Yeah, I shouldn’t. Sorry.”

Caitlin hugged him back, hoping her response would be soothing enough - one third because she had no idea how they would change the future, another third because a part of her wanted to glance back at Cassidy ( _make sure he's safe,_ it hissed, _he could undo his existence at any second)_ , and the last part of her mind was questioning everything she felt.

**Notes for the Chapter:**

> I love Cassidy. Pinky swear. 
> 
> I hope you enjoyed this chapter! Any and all comments/kudos/bookmarks will make my day.

**Author's Note:**

> Hi! Thanks for reading - Cassidy has been kicking around my head for a while now, and while I'm not necessarily confident updates for this story will be consistent, this was definitely enjoyable to write; ever since I watched season 5, I always wondered how Nora went survived a year in the past, and I was honestly disappointed at how little they explored that aspect of her origins. That, and while I personally suspect part of the reason we see so few metas that are minors is for laws surrounding child actors and such, I've always been intrigued by how the various heroes of the arrowverse would react to teen heroes.
> 
> Anyways, I hope you liked this chapter! Any and all kudos/bookmarks/comments will make my day.


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